This invention relates to a data recording/reproducing method and apparatus for recording speech or video data on a recording medium, to which random access can be had, such as a hard disc, and for reproducing the recorded data.
Recently, a random-accessible hard disc array device, composed of a large number of large-capacity hard disc devices and having a recording capacity of tens to hundreds of gigabytes (GB), has been put to practical use.
This hard disc array device is suited for recording speech data and/or video data of an extremely large data volume. In particular, the hard disc array device is superior as a recording/reproducing apparatus for an editing device because of its characteristics of reproducing given speech/video data in a short access time.
Meanwhile, the video data and the speech data are collectively recorded on the recording medium. If data is managed on the file basis, the video data and the speech data are handled as a set, so that the video data and the speech data cannot be handled separately from each other without difficulties.
The result is such defects that the number of channels of the speech data cannot be modified on the file basis partway, that the files of speech data with different number of channels cannot be made to co-exist and hence the number of speech channels has to be matched to the maximum number thus producing loss in the recording medium, that a recording area for images and the maximum number of the speech channels has to be used for data composed only of speech or data composed only of images, thus wasting the recording medium, and that the image only or optional speech channels only cannot be changed.
It is therefore an object of the present invention to provide a recording/reproducing method and apparatus for speech and/or video data whereby, in recording speech/video data, as plural editing objects, on a random-accessible recording medium, such as a hard disc or a magneto-optical disc (MO disc), and in reproducing optional speech/video data responsive to request from an external device, such as editing device, the video data and the speech data can be handled as independent files.
In one aspect, the present invention provides a data recording/reproducing apparatus including first data recording/reproducing means for recording a video data file on a random-accessible recording medium as one or more records each of which is a set of data continuous on the recording medium and for reproducing the recorded video data file, second data recording/reproducing means for recording a speech data file on the random-accessible recording medium as one or more records each of which is a set of data continuous on the recording medium and for reproducing the recorded speech data file, and data management means for managing the video data file and the speech data file, each recorded as one or more records on the recording medium, by a file entry, a video data record entry and a speech data record entry. The file entry has a file name of the video data file, a file name of the speech data file, a record entry number of a leading record of the video data and a record entry number of a leading record of the speech data file. The video data record entry is provided in association with each record of the video data file and has leading position data specifying the leading end of a recording area of the next record with data continuity and recording length data specifying the size of the recording area of the next record. The speech data record entry is provided in association with each record of the speech data file and has leading position data specifying the leading end of a recording area of the next record with data continuity and recording length data specifying the size of the recording area of the next record. The data recording/reproducing apparatus also includes means for managing a vacant area of video data present in a dispersed state on the recording medium by a video data vacant area list having a link data specifying the link state to the next vacant area, leading position data specifying the leading position of the vacant area and an areal length data specifying the size of the vacant area and means for managing a vacant area of speech data present in a dispersed state on the recording medium by a speech data vacant area list having a link data specifying the link state to the next vacant area, leading position data specifying the leading position of the vacant area and an areal length data specifying the size of the vacant area.
In another aspect, the present invention also includes a data recording/reproducing method including recording a video data file on a random-accessible recording medium as one or more records each of which is a set of data continuous on the recording medium and for reproducing the recorded video data file, recording a speech data file on the random-accessible recording medium as one or more records each of which is a set of data continuous on the recording medium and for reproducing the recorded speech data file, and managing the video data file and the speech data file, each recorded as one or more records on the recording medium, by a file entry, a video data record entry and a speech data record entry. The file entry having a file name of the video data file, a file name of the speech data file, a record entry number of a leading record of the video data and a record entry number of a leading record of the speech data file, while the video data record entry is provided in association with each record of the video data file and has leading position data specifying the leading end of a recording area of the next record with data continuity and recording length data specifying the size of the recording area of the next record, the speech data record entry provided in association with each record of the speech data file and having leading position data specifying the leading end of a recording area of the next record with data continuity and recording length data specifying the size of the recording area of the next record.
Preferably, the data recording/reproducing method additionally includes managing a vacant area of video data present in a dispersed state on the recording medium by a video data vacant area list having a link data specifying the link state to the next vacant area, leading position data specifying the leading position of the vacant area and an areal length data specifying the size of the vacant area, and managing a vacant area of speech data present in a dispersed state on the recording medium by a speech data vacant area list having a link data specifying the link state to the next vacant area, leading position data specifying the leading position of the vacant area and an areal length data specifying the size of the vacant area.
With the data recording and/or reproducing method and apparatus according to the present invention, in which and random-accessible video data recording and/or reproducing means and random-accessible speech data recording and/or reproducing means are provided separately from each other, and a video speech file and a speech data file, each recorded as one or more record by these data recording and/or reproducing means, is managed by data management means using a file entry, a video data record entry and a speech data record entry, the number of channels of the speech data can be changed at any time, while the speech data with different number of channels can be made to co-exist. Thus it becomes possible to handle data composed only of speech or video, or to change only the video or only an optional channel of the speech.